[英]Change index in array.map
I have a variable of the form: 我有一个形式的变量:
var data=[
{
start:22,
end: 8
},
{
start:60,
end: 43
},
{
start: 35,
end: 55
},
{
start:25,
end:40
}
];
I want to map it to look like this 我想把它映射成这样
var newData = { 22:8, 60:43, 35:55, 25:40};
Is this possible? 这可能吗? I mainly just want to use the start numbers as a key to access the end numbers without using search. 我主要只是想使用开始数字作为键来访问结束数字,而不使用搜索。 I have tried to do this: 我试图做到这一点:
var mapData = data.map(function(data){
var x = {};
x[data.start]=data.end;
return x;
});
but it gives: 0 : {22: 8} 1 : {60: 43} 2 : {35: 55} 3 : {25: 40} which means i have to use 0, 1,2, 3 as indices. 但它给出:0:{22:8} 1:{60:43} 2:{35:55} 3:{25:40}这意味着我必须使用0、1、2、3作为索引。
Only Array#map
does not work in this case, because without post processing, you get a single array with objects. 在这种情况下,只有Array#map
不起作用,因为如果不进行后期处理,您将获得带有对象的单个数组。 You need to combine all objects into a single object. 您需要将所有对象组合成一个对象。
With Object.assign
and spread syntax ...
, you get a single array with all properties from the objects in the array. 使用Object.assign
和spread语法...
,您可以从数组中的对象获得具有所有属性的单个数组。
var data = [{ start: 22, end: 8 }, { start: 60, end: 43 }, { start: 35, end: 55 }, { start: 25, end: 40 }], result = Object.assign(...data.map(({ start, end }) => ({ [start]: end }))); console.log(result);
You can use array.reduce: 您可以使用array.reduce:
var data=[ { start:22, end: 8 }, { start:60, end: 43 }, { start: 35, end: 55 }, { start:25, end:40 } ]; var res = data.reduce((m, o) => { m[o.start] = o.end; return m; }, {}); console.log(res);
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